Background Tasks

Use q.run() to execute functions in the background, in-process.

import timeimport randomfrom h2o_wave import main, app, Q, ui

def blocking_function(secs) -> str:    time.sleep(secs)  # Blocks!    return f'Done waiting for {secs} seconds!'

@app('/demo')async def serve(q: Q):    if q.args.start:        q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.progress('Running...')])        await q.page.save()
        seconds = random.randint(1, 6)
        # DON'T DO THIS!        # This will make your app unresponsive for some time:        # message = blocking_function(seconds)
        # Do this instead:        message = await q.run(blocking_function, seconds)
        q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.message_bar('info', message)])        await q.page.save()    else:        q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.button(name='start', label='Start')])        await q.page.save()

Tags:  background_tasks